Splice Resistance Measurements on 2G YBCO Coated Conductors

Rey, C.M.; Duckworth, R. C.; Zhang, Y.

doi:10.1109/tasc.2009.2019535

Cited by 14 publications

(6 citation statements)

References 4 publications

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“…Some studies claimed that there was no observable field dependence of R J [7,36]. Other studies demonstrated that R J of the samples fabricated using the same kind of CCs changed significantly with an applied magnetic field [37]. If resistive demountable joints are to help enable commercial fusion, they must be robust and reproducible and their resistances must be low enough under all operating conditions (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…in-field) to avoid large cryogenic costs or quenching the superconductor. There are also only limited studies on the temperature dependence of R J [37][38][39] which to date has meant there is no model for describing R J accurately nor is there a reliable estimate of the joint resistivity expected under operating conditions for different applications. Small scale, soldered joints will be an integral component of any large fusion joint between superconductors and are the focus of this paper.…”

Section: Introductionmentioning

confidence: 99%

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Soldered joints—an essential component of demountable high temperature superconducting fusion magnets

Tsui

Surrey

Hampshire

2016

Supercond. Sci. Technol.

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Demountable superconducting magnet coils would offer significant benefits to commercial nuclear fusion power plants. Whether large pressed joints or large soldered joints provide the solution for demountable fusion magnets, a critical component or building block for both will be the many, smaller-scale joints that enable the supercurrent to leave the superconducting layer, cross the superconducting tape and pass into the solder that lies between the tape and the conductor that eventually provides one of the demountable surfaces. This paper considers the electrical and thermal properties of this essential component part of demountable high temperature superconducting (HTS) joints by considering the fabrication and properties of jointed HTSs consisting of a thin layer of solder (In52Sn48 or Pb38Sn62) sandwiched between two rare-earth-Ba2Cu3O7 (REBCO) second generation HTS coated conductors (CCs). The HTS joints are analysed using numerical modelling, critical current and resistivity measurements on the joints from 300 to 4.2 K in applied magnetic fields up to 12 T, as well as scanning electron microscopy studies. Our results show that the copper/silver layers significantly reduce the heating in the joints to less than a few hundred mK. When the REBCO alone is superconducting, the joint resistivity (RJ) predominantly has two sources, the solder layer and an interfacial resistivity at the REBCO/silver interface (∼25 nΩ cm2) in the as-supplied CCs which together have a very weak magnetoresistance in fields up to 12 T. We achieved excellent reproducibility in the RJ of the In52Sn48 soldered joints of better than 10% at temperatures below Tc of the REBCO layer which can be compared to variations of more than two orders of magnitude in the literature. We also show that demountable joints in fusion energy magnets are viable and need only add a few percent to the total cryogenic cost for a fusion tokamak.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Soldered joints—an essential component of demountable high temperature superconducting fusion magnets

Tsui

Surrey

Hampshire

2016

Supercond. Sci. Technol.

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“…Thus, welding is the easiest method for joint manufacturing. For this reason, soft welding remains the most widely used approach for splicing different commercial coated conductors [24,25]. With this technique, coated conductors can be applied 'as-received', although special attention should be paid to the type of solder used and the processing parameters for spliced joints to achieve low resistance joints.…”

Section: Introductionmentioning

confidence: 99%

Effect of the axial stress and the magnetic field on the critical current and the electric resistance of the joints between HTS coated conductors

Konstantopoulou¹,

Sarazin²,

Granados³

et al. 2015

Supercond. Sci. Technol.

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High temperature superconducting (HTS) wires require a detailed characterization of the possible degradation of their properties by handling at room temperature as well as during their service life, establishing the limits for associated functional devices and systems. In this paper, we study the mechanical behavior of spliced joints between commercial HTS coated conductors based on YBCO at room (300 K) and service temperatures (77 K). Single lap shear tests were performed and the evolution of the critical current and electric resistivity of the joints were measured. The complete strain field for the tape and joints was also obtained by digital image correlation. In addition, tensile tests under an external magnetic field were performed, and the effect of the applied field on the critical current and electric resistivity of the joints were studied. Finally, finite element simulations were employed to reproduce the distribution of the stress field developed in the spliced joint samples during axial loading.

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“…Tests on initial solder joint samples showed non-linear voltage versus current curves, with voltage growing rapidly with current beyond some transition point. While some groups report good joints using standard lead tin solder [8,3], our experience with the non-standard narrow tapes contradicts this. One difference with these studies is that both used tapes with a relatively thick ($20 lm) copper stabilizer layer on the outer surface.…”

Section: Transition Boardsmentioning

confidence: 55%